"We encounter Jesus in those who are poor, rejected, or refugees. Do not let fear get in the way of welcoming our neighbor in need," another read.

He is the latest religious leader to condemn practices by some nations to slow the movement of migrants seeking asylum. President Donald Trump has received numerous calls to reverse a policy by which asylum seekers from Latin America are separated from their children upon entry to the United States. Among the critics is the United States Conference of Catholic Bishops, which represents Catholic clergy and earlier this month issued a strong condemnation of the practice.

"Families are the foundational element of our society and they must be able to stay together," wrote Cardinal Daniel DiNardo, the president of the conference. "While protecting our borders is important, we can and must do better as a government."

About 70 million self-described Catholics live in the United States, or about 24 percent of the population. By a margin of 52 to 46 percent, they favored Trump over Hillary Clinton in the 2016 presidential election.

Evangelical Protestant leaders, who largely support Trump, have also been outspoken in their disapproval of the U.S. border policy. The Evangelical Immigration Table, a coalition of organizations who seek immigration reform "consistent with biblical values," issued a statement this month opposing the administration's policy.

"The traumatic effects of this separation on these young children, which could be devastating and long-lasting, are of utmost concern," it said.

The statement was signed by Russell Moore of the Southern Baptist Convention, Scott Arbeiter, of World Relief and Leith Anderson, the president of the National Association of Evangelicals and Samuel Rodriguez, the president of the National Hispanic Christian Leadership Conference. While Moore has been a critic of the Trump administration, the others have split with the administration on the issue.

The pope's comments came as the German government faces collapse over its lenient immigration policy, under which one million migrants have entered the country since 2015. Wednesday, the Hungarian government passed a set of laws making it a crime to aid undocumented immigrants.